[MikeD_VA]

At the end of a two hour drive I heard a loud noise coming from under the hood. Drove the car the next day for a couple of quick trips, heard noise again after shutting down. At first I thought the cooling fan was running but checked and found it wasn’t. Checked codes and found codes consistent with water pump failure (3847, 378F, 3446). With the car off the pump would run (noisily) and I could hear water circulating. No over heating.

Ordered parts (pump, thermostat, bolts, coolant) from oembimmerparts.com. The challenge was then to get the car to my weekend house where I have a lift, that is more than an hours drive. Having read other’s accounts of failure and the noise preceding the failure I decided to chance it. I used the “secret menu” to get the coolant temp displayed. Got stuck in traffic getting out of the city, never saw more than 102 C. Made the trip just fine, shut the car down and still heard the noise. The noise sounds like a weed whacker running off in the distance.

Got the car on the lift and began disassembly. Managed to drain most of the coolant without getting drenched or making a mess. Everything came apart without issue except for the larger of the two quick disconnect hoses. That required a large pry bar carefully placed so as not to break anything. Reassembly went okay except the quick disconnect needed serious force to reconnect. Put the sway bar and power steering line back in place, left the underbody cladding off so I could check for leaks later. Filled with coolant, ran the purge procedure. Got car up to temp and verified no leaks. Replaced underbody panel.

Total repair time not including research (YouTube, searching this forum) just under 5 hours. Thanks to posters that provided their accounts of failure/replacement and posting about the “secret menu”.